5503898
Description
Flashcards by Zayed Zaker, updated more than 1 year ago
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Created by Zayed Zaker
over 8 years ago
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| Question | Answer |
| What is Diffusion? | Diffusion is the process by which particles of a substance spread out from each other, moving from a region where they are in high concentration to a region of low concentration. |
| What is a concentration gradient? | It is the space in which particles of a substance will move down until they are evenly spread |
| When can diffusion only happen? | Particles in the substance must be dissolved and there must be a concentration gradient present between the solutions on either side of the cell membrane. |
| Give two examples of Diffusion and what happens? | Gas exchange in the lungs move oxygen from alveolus region to blood circulating in lungs- gas exchange in leaf moves carbon dioxide into air spaces in leaf |
| What is active transport? | Active transport is a transport process which is used to move dissolved molecules from low concentration to high concentration, against a concentration gradient |
| What does active transport require? | Requires energy from respiration in order to take place. |
| How is active transport carried out? | Active transport is carried out by a series of protein carriers within the cell membrane- these allow dissolved substances to move across membrane by changing shape |
| Give two examples of active transport? | Root hair cells in plant roots use active transport to absorb mineral ions (such as nitrates) from the soil- Small intestine villi cells use active transport alongside diffusion to maximize the absorption of glucose and other substances, eg minerals |
| What is osmosis? | Osmosis is the movement of water from a more dilute solution to a less dilute solution from a permeable membrane |
| What is a partially permeable membrane? | A partially permeable membrane allows small, soluble molecules like water to pass through it freely - but prevents larger molecules from doing so |
| What happens when water doesn't move to the other side? | There is no overall (net) movement of water. |
| What happens if solutions are less dilute outside the animal cell? | Water will move out and the cell will shrivel up (hyper tonic). |
| What would be the effect in plant cells? | in plant cells this would cause the membrane and cytoplasm to shrink away from the cell wall, causing the plant cell to become flaccid |
| What is the opposite effect in animal and plant cell? | The animal cell may burst due to water in and plant cells become turgid as cell wall prevents further expansion due to water(hypotonic) |
| What is the problem with more complex organisms in diffusion? | Diffusion distance is longer and there is a larger volume inside body |
| What do cells need to function effeiciently and effectively? | Enough mineral ions, water and glucose from respiration |
| Why are sport drinks more efficient to the athlete than soft drinks? | It has levels of water, sugar and mineral content that is enough to re hydrate the athlete and make them work longer |
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